Abstract: A hierarchical object recognition method for aggregation, interpretation and classification of information from multiple sensor sources on the detection feature attribute level. The system extracts information derived from each sensor source to obtain detections and their feature attributes. At least two processing streams, one for each sensor source, are provided for converting the detections and their feature attributes into hypotheses on identity and class of detected objects. The detections are shared and combined between the two processing streams using hierarchical information fusion algorithms to determine which ones of the hypotheses on identity and class of detected objects have sufficient probabilities for classifying the information.

Abstract: A downhole tool connectable to a drill string by a connection atop the tool includes a mandrel for connection with the drill string, the mandrel being rotatable within a body. A plurality of blades are individually extendible radially from the body to engage the wall of a well bore, the radial position of the blades being adjustable between a first retracted position and a second extended position to position the centre line of the mandrel at a desired position relative to the longitudinal axis of the well bore. A positioning system is provided to hold each of the blades at the retracted position, the extended position or at any intermediate position therebetween.